A police car blowing through a red light led to a spectacular smashup on a Chelsea street last month that badly injured one man and cost another his life.

Jack Vanleuvan, 61, died on Nov. 2 after spending almost a month in a coma from the multivehicle crash caused by the police cruiser, which witnesses say gave little to no warning before running the light.

Vanleuvan was a Chelsea native and a father of four, and “all four of them lost their best friend that day,” said his daughter-in-law, Toni Vanleuvan.

The tragic incident happened at around 11 p.m. Oct. 4, when Vanleuvan was driving a van across West 25th Street at Eighth Avenue, cops said.

That’s when a police cruiser responding to an emergency call suddenly darted out into the traffic crossing 25th Street. It was hit by the van that then went careening into a cab, two pedestrians and a bicyclist and finally a building.

Charles Arnold, a lawyer for Sacherman, said his investigators have spoken to several witnesses.

“Everyone that we’ve talked to thus far indicates that the police either flashed their lights at the last second or didn’t have them on at all. No one that we’ve talked to has said anything about sirens,” Arnold said.

In the police report, the driver, Officer Sean Fleming, said he had his lights and siren on.